Anode Material For Li-ion Batteries Research Articles

The oxidation reaction mechanism and its kinetics for a carbonaceous precursor prepared from ethylene tar for use as an anode material for lithium-ion batteries

The oxidation reaction mechanism and its kinetics for ethylene tar were investigated in order to obtain a suitable anode material for Li-ion batteries. The oxidation of ethylene tar was divided into 3 stages (350–550, 550–700 and 700–900 K) according to the thermogravimetric curve. To reveal the oxidation reaction mechanism, the components of the gases evolved at different stages were analyzed by mass spectrometry and infrared technology. Based on these results the reaction was divided into 4 stages (323–400, 400–605, 605–750 and 750–860 K) to perform simulation calculations of the kinetics. Using the iso-conversion method (Coats-Redfern) to analyze the linear regression rates (R2) between 17 common reaction kinetics models and experimental data, an optimum reaction kinetics model for expressing the oxidation of ethylene tar was determined and the results were as follows. (1) During oxidation, the side chains of aromatic compounds first react with oxygen to form alcohols and aldehydes, leaving peroxy-radicals on aromatic rings. Subsequently, the aromatic compounds with peroxy-radicals undergo polymerization/condensation reactions to form larger molecules. (2) A fourth-order reaction model was used to describe the first 3 stages in the oxidation process, and the activation energies are 47.33, 18.69 and 9.00 kJ·mol−1 at 323–400, 400–605, 605–750 K, respectively. A three-dimensional diffusion model was applied to the fourth stage of the oxidation process, and the activation energy is 88.37 kJ·mol−1 at 750–860 K. A high softening point pitch was also produced for use as a coating of the graphite anode, and after it had been applied the capacity retention after 300 cycles increased from 51.54% to 79.07%.

Porous High-Entropy Oxide Anode Materials for Li-Ion Batteries: Preparation, Characterization, and Applications.

High-entropy oxides (HEOs), as a new type of single-phase solid solution with a multi-component design, have shown great potential when they are used as anodes in lithium-ion batteries due to four kinds of effects (thermodynamic high-entropy effect, the structural lattice distortion effect, the kinetic slow diffusion effect, and the electrochemical "cocktail effect"), leading to excellent cycling stability. Although the number of articles on the study of HEO materials has increased significantly, the latest research progress in porous HEO materials in the lithium-ion battery field has not been systematically summarized. This review outlines the progress made in recent years in the design, synthesis, and characterization of porous HEOs and focuses on phase transitions during the cycling process, the role of individual elements, and the lithium storage mechanisms disclosed through some advanced characterization techniques. Finally, the future outlook of HEOs in the energy storage field is presented, providing some guidance for researchers to further improve the design of porous HEOs.

Heterometallic-organic frameworks containing Fe(II) nodes as high-performance anode materials for Li-ion batteries

Heterometallic-organic frameworks containing Fe(II) nodes as high-performance anode materials for Li-ion batteries

CoS2 nanoparticles embedded in N-doped hollow carbon nanotubes as anode materials for high performance lithium-ion battery

CoS2 nanoparticles are effectively incorporated into N-doped hollow carbon nanotubes (CoS2@HC) through a combination of a straightforward oil bath method and a high-temperature sulfurization process. The CoS2@HC composite demonstrates exceptional electrochemical performance as an anode material in Li-ion batteries. The outstanding performance of this system can be attributed to the ingeniously designed hollow carbon nanotubes. These nanotubes not only possess high electrical conductivity, thus facilitating efficient electron transfer, but also provide ample space to accommodate volume changes. Furthermore, the ultrafine CoS2 nanoparticles embedded within the hollow carbon nanotubes offer a large surface area for effective electrolyte wetting and rapid ion diffusion during the cycling process. As a result, the CoS2@HC composite delivers a high capacity of 356.2 mAh·g−1 at 2000 mA·g−1 even after 1500 cycles, demonstrating remarkable cyclic stability.

Si Nanowires: From Model System to Practical Li-Ion Anode Material and Beyond.

Nanowire (NW)-based anodes for Li-ion batteries (LIBs) have been under investigation for more than a decade, with their unique one-dimensional (1D) morphologies and ability to transform into interconnected active material networks offering potential for enhanced cycling stability with high capacity. This is particularly true for silicon (Si)-based anodes, where issues related to large volumetric expansion can be partially mitigated and the cycle life can be enhanced. In this Perspective, we highlight the trajectory of Si NWs from a model system to practical Li-ion battery anode material and future prospects for extension to beyond Li-ion batteries. The study examines key research areas related to Si NW-based anodes, including state-of-the-art (SoA) characterization approaches followed by practical anode design considerations, including NW composite anode formation and upscaling/full-cell considerations. An outlook on the practical prospects of NW-based anodes and some future directions for study are detailed.

First-Principles Studies on Transition Metal Doped Mo2B2 as Anode Material for Li-Ion Batteries.

New two-dimensional (2D) transition-metal borides have attracted considerable interest in research on electrode materials for Li-ion batteries (LIBs) owing to their promising properties. In this study, 2D molybdenum boride (Mo2B2) with and without transition metal (TM, TM=Mn, Fe, Co, Ni, Ru, and Pt) atom doping was investigated. Our results indicated that all TM-doped Mo2B2 samples exhibited excellent electronic conductivity, similar to the intrinsic 2D Mo2B2 metal behavior, which is highly beneficial for application in LIBs. Moreover, we found that the diffusion energy barriers of Li along paths 1 and 2 for all TM-doped Mo2B2 samples are smaller than 0.30 and 0.24 eV of the pristine Mo2B2. In particular, for 2D Co-doped Mo2B2, the diffusion energy barriers of Li along paths 1 and 2 are reduced to 0.14 and 0.11 eV, respectively, making them the lowest Li diffusion barriers in both paths 1 and 2. This indicates that TM doping can improve the electrochemical performance of 2D Mo2B2 and that Co-doped Mo2B2 is a promising electrode material for LIBs. Our work not only identifies electrode materials with promising electrochemical performance but also provides guidance for the design of high-performance electrode materials for LIBs.

A Study on the Nanostructural Evolution of Bi/C Anode Materials during Their First Charge/Discharge Processes.

As a candidate anode material for Li-ion batteries, Bi-based materials have attracted extensive attention from researchers due to their high specific capacity, environmental friendliness, and simple synthesis methods. However, Bi-based anode materials are prone to causing large volume changes during charging and discharging processes, and the effect of these changes on lithium storage performance is still unclear. This work introduces that Bi/C nanocomposites are prepared by the Bi-based MOF precursor calcination method, and that the Bi/C nanocomposite maintains a high specific capacity (931.6 mAh g-1) with good multiplicative performance after 100 cycles at a current density of 100 mA g-1. The structural evolution of Bi/C anode material during the first cycle of charging and discharging is investigated using in situ synchrotron radiation SAXS. The SAXS results indicate that the multistage scatterers of Bi/C composite, used as an anode material during the first lithiation, can be classified into mesopores, interspaces, and Bi nanoparticles. The different nanostructure evolutions of three types of Bi nanoparticles were observed. It is believed that this result will help to further understand the complex reaction mechanism of Bi-based anode materials in Li-ion batteries.

Fabrication of Li4Ti5O12 (LTO) as Anode Material for Li-Ion Batteries.

The most popular anode material in commercial Li-ion batteries is still graphite. However, its low intercalation potential is close to that of lithium, which results in the dendritic growth of lithium at its surface, and the formation of a passivation film that limits the rate capability and may result in safety hazards. High-performance anodes are thus needed. In this context, lithium titanite oxide (LTO) has attracted attention as this anode material has important advantages. Due to its higher lithium intercalation potential (1.55 V vs. Li+/Li), the dendritic deposition of lithium is avoided, and the safety is increased. In addition, LTO is a zero-strain material, as the volume change upon lithiation-delithiation is negligible, which increases the cycle life of the battery. Finally, the diffusion coefficient of Li+ in LTO (2 × 10-8 cm2 s-1) is larger than in graphite, which, added to the fact that the dendritic effect is avoided, increases importantly the rate capability. The LTO anode has two drawbacks. The energy density of the cells equipped with LTO anode is lower compared with the same cells with graphite anode, because the capacity of LTO is limited to 175 mAh g-1, and because of the higher redox potential. The main drawback, however, is the low electrical conductivity (10-13 S cm-1) and ionic conductivity (10-13-10-9 cm2 s-1). Different strategies have been used to address this drawback: nano-structuration of LTO to reduce the path of Li+ ions and electrons inside LTO, ion doping, and incorporation of conductive nanomaterials. The synthesis of LTO with the appropriate structure and the optimized doping and the synthesis of composites incorporating conductive materials is thus the key to achieving high-rate capability. That is why a variety of synthesis recipes have been published on the LTO-based anodes. The progress in the synthesis of LTO-based anodes in recent years is such that LTO is now considered a substitute for graphite in lithium-ion batteries for many applications, including electric cars and energy storage to solve intermittence problems of wind mills and photovoltaic plants. In this review, we examine the different techniques performed to fabricate LTO nanostructures. Details of the synthesis recipes and their relation to electrochemical performance are reported, allowing the extraction of the most powerful synthesis processes in relation to the recent experimental results.

Carbons Derived from Regenerated Spherical Cellulose as Anodes for Li-Ion Batteries at Elevated Temperatures.

Biomass-based materials have emerged as a promising alternative to the conventional graphite anode in Li-ion batteries due to their renewability, low cost, and environmental friendliness. Therefore, a facile synthesis method for porous hard carbons based on cellulose acetate microspheres and bead cellulose is used, and their application as anode materials in Li-ion batteries is discussed. The resulting porous carbons exhibit promising electrochemical characteristics, including a reversible capacity of about 300 mAh g-1 at 0.1 C (37 mA g-1) after 50 cycles, and stable capacities up to 210 mAh g-1 over 1000 cycles at 1 C (372 mA g-1) in half-cells for cellulose acetate microspheres carbonised at 1200 °C. Moreover, at 60 °C cellulose-derived carbons show higher specific capacities than graphite (300 mAh g-1 vs 240 mAh g-1 at 1 C after 500 cycles), indicating their potential for use in high-temperature applications. The different charge storage mechanisms of the prepared hard carbon materials and graphite are observed. While capacity of graphite is mainly controlled by the Faradaic redox process, the cellulose-derived carbons combine Faradaic intercalation and capacitive charge adsorption.

Amorphous CoO/Al2O3/C hybrid as anode material for fast-charging Li-ion batteries

Amorphous CoO/Al2O3/C hybrids were synthesized using a simple pyrolysis method at various temperatures and reagent ratios. At 500 °C, CoO localized from homogenous distribution to quantum dots (∼10 nm) on the Al2O3/C matrix. X-ray photoelectron spectroscopy results suggested that the feed nitrate ions doped the hybrids with pyridinic (398.8 eV) and pyrrolic (400.55 eV) N, which ameliorated the electrochemical performance of the hybrids. The optimum pyrolysis temperature to obtain a reversible capacity of 0.45 Ah g−1 at the 1000th cycle at a current density of 1 A g−1 was 500 °C. However, owing to the polarization electrode, the specific capacity decreased by 54 % after increasing the material mass loading (0.5–3 mg cm−2), which resulted in a maximum areal capacity of 0.78 mAh cm−2. After regulating the C content in the hybrid, the loss in reversible capacity was only 29 % for an eight-fold gain in the mass-loading (0.4–3.2 mg cm−2) and the areal capacity was up to 1.13 mAh cm−2. The specific capacity of the optimized electrode was 0.52 Ah g−1 at the 1000th cycle. In addition, it only lost 28 % of its capacity along with a ten-fold increase in current density (0.2–2 A g−1). In a full cell test involving a LiNi0.8Mn0.1Co0.1O2-based cathode and a CoO/Al2O3/C-based anode, 91 % of the maximum theoretical specific capacity was obtained, whereas the capacity retention at the 100th cycle was 97 %. Electrochemical impedance spectra suggested that small resistances (<38 Ω) and high Li+ diffusivity (5.5–6.8 × 10−11 cm2 s−1) supported the fast-charging properties of the hybrid.

Characterization of ultrafast-laser ablation of micro-structures in Li-ion battery anode and cathode materials: Morphology, rate, and efficiency

Characterization of the rate and quality of ultrafast-laser ablation of Li-ion battery (LIB) electrode materials is presented for a collection of common and next-generation electrodes. Laser ablated micro-structures on the surface of LIB electrodes have been shown to provide dramatic enhancement of high-rate capability and electrode wetting. However, industrial adoption is hampered by a lack of data enabling informed choice of laser parameters and predicting process throughput. This work bridges this gap by providing characterization of the ablation process at more laser parameters (laser fluence and number of pulses used) than are currently available in the literature. Further, we expand on previous graphite and lithium iron phosphate (LFP) ablation work by extending ablation characterization to new LIB materials, providing high data resolution and adopting new characterization metrics which are relevant for industrial application of this technology. Ablated pores are characterized by their ablated depth, volume, and how the depth and volume ablation rate changes as a function of pore depth. Finally, we provide a detailed characterization of the morphology of laser ablated micro-structures which informs how material and laser parameters affect the quality of laser-processed electrodes.

Electrochemical performance evaluation of a Ni/Fe mixed oxide natural clay composite as anode material for Li-ion batteries

A Ni/Fe mixed oxide natural clay composite was obtained by simple addition of bentonite natural clay sample after coprecipitation of layered double hydroxide (Ni0.75Fe0.25(OH)2(CO3)0.125) precursor; later this composite was sintered at 400 °C. The natural clay was collected from La Plata city (Argentina), and this has been used without further purification treatment. The electrochemical characterization allowed to identify stability improvement of the charge-discharge capacity values for the materials with calcination (35 % capacity retention after 60 cycles) against an anode prepared without clay (only 8 % retention). However, the anodic material without clay delivered a higher discharge capacity than the anode material with clay, as expected, due to the lacking the non-electroactive clay quantity. Physical characterization of the materials, such as nitrogen physisorption, showed a smaller particle diameter (37 nm against 54 nm) for the mixed oxides with and without natural clay, respectively. Despite this, by scanning electron microscopy a greater size difference was observed in the morphology for the oxide- natural clay composites. This could be because the smaller particle size along the interstitial space of the consecutive clay flakes and the pore volume of the material could be produced a synergistic effect between them; and thus promote a buffered volumetric expansion. This is generally reported to be responsible for the low charge- discharge cyclic performance observed in the conversion anodes. Also, the process of re-dissolution of the hydroxide precursor in the basic media, followed by the double hydroxide re-precipitation from Ni+2 and Fe+3 which are adsorbed in negative sites of the clay could be responsible for the achievement of the smaller size particles.

One-dimensional van der Waals V2Se9 as a conversion-type anode material for advanced Li rechargeable batteries

Volume expansion of active materials during lithium storage is one of the main issues in Li-ion batteries (LIBs) that should be addressed. In particular, large volume changes and particle cracking are problematic for electrode materials based on conversion reaction, which are considered attractive anode materials with high energy densities. In this study, a one-dimensional van der Waals (1D vdW) material, V2Se9, is proposed as a conversion-type anode material for LIBs. The V2Se9 electrode material has a 1D chain molecular structure with vdW interactions between chains to form a bulk crystal structure. The spaces between the 1D chains act as structural buffers and provide short Li+ diffusion paths that can improve the electrochemical performance of the electrode materials. The V2Se9 electrode exhibits a high reversible capacity of 563.3 mAh g−1 at 100 mA g−1 and a high rate capability of 109.1 mAh g−1 at 3200 mA g−1. The capacity retention of V2Se9 electrodes is 83.72% after 100 cycles. Synchrotron X-ray diffraction and X-ray absorption spectroscopy reveal the formation of Li2Se and V metal, indicating that Li ion storage occurs via the conversion reaction. The structural stability of V2Se9 is demonstrated using SEM measurements of the discharged and charged V2Se9 electrodes during cycling. These results demonstrate the reaction mechanism of V2Se9 and highlight the potential of 1D vdW materials as high-performance anode materials in LIBs.

Pitaya-inspired Li Metal-free Prelithiation of silicon monoxide into anode materials for Li-ion batteries

Silicon monoxide (SiO), which has been verified as a potential anode material, can improve the energy density of Li-ion batteries (LIBs). These LIBs are crucial for the advancement of electric vehicles. However, the commercial application of SiO is severely limited due to poor initial Coulombic efficiency (ICE). In this study, we present a novel concept to enhance the ICE of silicon oxide-based anodes by collaboratively leveraging two distinct reaction theories: disproportionation reaction and the reaction between acidic oxide and alkali. Based on this concept, we utilize a chemical disproportionation-driven Li metal-free prelithiation method, enabling the in-situ growth of microcrystalline silicon and lithium silicate within amorphous silicon oxide, which bears a striking resemblance to pitaya seeds. This reaction yields unique lithium silicate and nano/micro-structured silicon surrounded by SiO (Si–SiO–LixSiOy multicomponents, PD-SiO). This can be demonstrated via transmission electron microscopy (TEM), Electron energy loss spectroscopy (EELS) or X-ray photoelectron spectroscopy (XPS). The reaction product, PD-SiO, exhibits remarkable properties, including high ICE (82.5 %), high charging capacity (1419 mAh g–1), and highly stable cycling performance (94.6 % capacity retention after 200 cycles at 0.5 A g–1). This study offers a new approach to enhance the initial Coulombic efficiency of silicon monoxide.

High-performance lithium storage in Li2SnO3-graphite composite enabled by Ag3Sn nanoparticles and oxygen vacancies

With high capacity (653 mAh g−1) and low voltage (0.6 V), Li2SnO3 is considered as a prospective anode material for Li-ion batteries (LIBs). Nevertheless, its practical uses are restricted by inferior electrochemical kinetics and fast capacity decay. Herein, a novel ternary composite of Ag3Sn alloy-lithium stannate-graphite (denoted as Ag3Sn-Li2SnO3-x-G) is designed and fabricated by ball milling and vacuum annealing. In this ternary composite, oxygen vacancy-containing Li2SnO3 and Ag3Sn alloy nanoparticles are homogeneously dispersed in the exfoliated graphite nanosheets. The introduction of Ag3Sn nanoparticles and oxygen vacancies into Li2SnO3-graphite can significantly enhance charge transport kinetics and structure stability of composite during the lithiation and delithiation processes. Benefiting from these merits, the Ag3Sn-Li2SnO3-x-G composite presents excellent cycling stability (782.4 mAh g−1 at 0.2 A g−1 after 200 cycles) and impressive rate capability (251.5 mAh g−1 at 2 A g−1). Broadly, this design strategy can provide an effective and reliable route for constructing advanced metal oxide-based anode materials for high-energy LIBs.

Ultrahigh energy density BeN monolayer: A nodal-line semimetal anode for Li-ion batteries

Topological quantum materials have significant potential for application as anode materials due to their intrinsically high electronic conductivity against perturbation from defects or impurities. In this work, we utilize a combination of a swarm-intelligence structure search method and first-principles calculations to predict the global minimum of a BeN monolayer, suggesting it as a promising nodal-line semimetal anode for Li-ion batteries. BeN anode demonstrates a substantial specific capacity of 3489 mAh/g and a low average open-circuit voltage of 0.15 V, resulting in an ultrahigh energy density of 9681 mWh/g (referenced to the standard hydrogen electrode potential). This energy density represents the highest among all two-dimensional (2D) topological quantum anodes and surpasses that of most currently known 2D anode materials for Li-ion batteries. Furthermore, the formation of a vacancy in the BeN monolayer induces a unique “self-doping” effect that promotes high electronic conductivity. Additionally, the BeN monolayer exhibits a diffusion energy barrier of 0.30 eV for Li-ion migration, a small-scale area expansion of 0.96% during the process of lithiation, and excellent wettability with the contacted electrolytes. Published by the American Physical Society 2024

First-principles calculation of electronic properties and diffusion barriers of Sc2CCl2 and Sc2CF2 for metal (Li, Na, K) ion batteries

MXenes have emerged as promising candidate for energy storage devices because of their superior properties. In this work, the electronic properties, low open circuit voltage (OCV) and diffusion barrier of Li, Na, K adsorption on Sc2CCl2 and Sc2CF2 monolayers are investigated by density functional theory. The most stable adsorption site is confirmed because of the shortest adsorption height and largest adsorption energy. The adsorptions of Li/Na/K on Sc2CCl2 and Sc2CCF2 induce the semiconductor–metal transition. Na-Sc2CF2 and Li-Sc2CF2 have higher theoretical capacity (CM), low open circuit voltage (OCV) and diffusion barriers, so they are more suitable as anode materials for Na-ion and Li-ion batteries. The analysis of charge transfer indicates that the adsorbed atoms in Sc2CF2 monolayer lose more electrons than the adsorbed atoms in Sc2CCl2 system because of stronger electronegativity of F.

Hexagonal Mg2B2 and Ca2B2 monolayers as promising anode materials for Li-ion and Na-ion batteries.

Exploring new high-performance anode materials is of great significance for next generation renewable energy technologies. Two-dimensional (2D) transition metal borides, named as MBenes, are receiving increasing attention in energy storage fields due to their structure-and-composition diversities and high electrical conductivities. Expanding the family of hexagonal MBenes to non-transition metal borides, we report two hexagonal IIA metal M2B2-typed MBenes and demonstrate the feasibility of exfoliation and application as anode materials for Li-ion batteries (LIBs) and Na-ion batteries (SIBs) using ab initio calculations. The predicted 2D Mg2B2 and Ca2B2 monolayers exhibit robust thermal and mechanical stabilities, inherent metallic properties, electrical conductivities, and excellent electrode performance. The outstanding theoretical specific capacities of Mg2B2 and Ca2B2 for Li/Na ions reach up to 764/527 and 859/527 mA h g-1, respectively. Furthermore, the average open-circuit voltages (OCVs) of Mg2B2 and Ca2B2 range from 0.275 to 0.395 V, indicating their suitability for anode materials. Additionally, the low diffusion energy barriers of Mg2B2 and Ca2B2 for Li/Na ions at delithiated/desodiated states (27/14 and 16/12 meV) and lithiated/sodiated states (187/58 and 52/34 meV) illustrate their excellent charge-discharge capabilities. These intriguing findings demonstrate the superior performance of the predicted IIA metal boride monolayers as promising anode materials for LIBs and SIBs and break through the limitations of transition metal MBenes as anode materials in terms of overall performance. Our study opens the door to the application of the main group metal MBenes in ion energy storage.

Exploring the potential of MB2 MBene family as promising anodes for Li-ion batteries.

In recent years, finding high-performance energy storage materials has become a major challenge for Li-ion batteries. B-based two-dimensional materials have become the focus of attention because of their abundant reserves and non-toxic characteristics. A series of two-dimensional transition metal borides (MBenes) are reported and their electrochemical properties as anode materials for Li-ion batteries are investigated by density functional theory (DFT) calculations. The surface of MB2 possesses medium adsorption strength and diffusion energy barrier for Li atoms, which are conducive to the insertion and extraction of Li-ions during the charge/discharge process of Li-ion batteries. Herein, we explore the potential of MB2 (M = Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu and Zn) as the anode material for LIBs. Excitingly, the Li atom can be stably adsorbed on the surface of MB2 (M = Sc, Ti, V, Nb, Mo, W) monolayers, and the theoretical capacity of the MB2 monolayer is high (521.77-1610.20 mA h g-1). The average open circuit voltage range is within 0.10-1.00 V (vs. Li/Li+). The relationship between the p-band center of the B atom and the adsorption energy of Li on the surface of MB2 is also investigated. Furthermore, it is found that the charge transfer of Li atom and metallic center in the most stable position is strongly related to the corresponding value of diffusion energy barrier. These results confirm that MB2 monolayers are promising 2D anode materials for Li-ion batteries, demonstrating the application prospects of B-based 2D materials.

High-areal capacity Si architecture as an on-chip anode for lithium-ion batteries

Silicon is one of the most promising anode materials for Li-ion batteries, especially to meet the growing demand for energy storage in the form of microbatteries for mobile and autonomous devices. However, the development of such batteries is hindered by mechanical and electrochemical failures resulting from massive Si volume expansion and continuous growth of the solid electrolyte interphase. In this study, we propose a novel on-chip anode architecture using rapid thermal annealing on porous silicon. The structure consists of a densified silicon layer on top of an isotropic structure of a porous layer. We demonstrate that this structure enhances both electrochemical and mechanical stabilities, achieving an areal capacity of 9 mAh cm−2 over more than 200 cycles with a high Coulombic efficiency near 100%.